Software-Defined Radio (“SDR”) is a rapidly evolving technology that is receiving enormous recognition and generating widespread interest in the telecommunication industry. Over the last few years, analog radio systems are being replaced by digital radio systems for various radio applications in military, civilian and commercial spaces. In addition, programmable hardware modules are increasingly being used in digital radio systems at different functional levels. One goal of SDR is to take advantage of these programmable hardware modules to build an open-architecture based radio system software protocol.
SDR technology facilitates implementation of some of the functional modules in a radio system such as modulation/demodulation, signal generation, coding and link-layer protocols in software. This enables reconfigurable software radio systems where dynamic selection of parameters for each of the above-mentioned functional modules is possible. A complete hardware based radio system has limited utility since parameters for each of the functional modules are fixed. A radio system built using SDR technology extends the utility of the system for a wide range of applications that use, for example, different link-layer protocols and modulation/demodulation techniques.
The commercial wireless communication industry is currently facing problems due to, for instance, the constant evolution of link-layer protocol standards (2.5 G, 3 G and 4 G), the existence of incompatible wireless network technologies in different countries which inhibits the deployment of global roaming facilities, and in rolling out new services and/or features to the vast number of legacy subscriber radios which may not be 100% compatible with each other.
SDR solves these problems by implementing the radio functionality as software modules running on a generic hardware platform. Further, multiple software modules implementing different standards can be stored in the radio system. The system can take on different “personalities” depending on the software module being used. Additionally, the software modules that implement new services and/or features can be downloaded over the air onto the radios. These examples of the flexibility offered by SDR systems is indicative of the capabilities of SDR systems in dealing with problems due to the existing plethora of radio standards and issues related to deployment of new services and/or features.
The U.S. military also has a significant radio interoperability problem. The story is often told of army troops calling in air support to Grenada using their personal calling cards and using Fort Bragg as an intermediary to communicate.
Interoperability problems are also an obstacle in international joint operations (military and/or civilian), where each nation typically has its own radio systems and standards. Recent emphasis on peacekeeping, disaster relief, homeland security and other non-combat military operations has exacerbated the problem. In these roles, military units must communicate with public safety agencies, humanitarian organizations, and the civilian population. A single SDR device with the ability to support multiple waveforms significantly reduces the number of devices needed in the field. For military users, who must maintain, transport, supply power to, and manage each device under challenging operational conditions, the benefit of a streamlined system is substantial.
SDR also promises to reduce military radio development and acquisition cost. Without SDR, new device development requires investing anew in the implementation of each supported communication standard. With SDR, the bulk of implementation knowledge for a communication standard is captured in portable software, which can be reused at low cost in new or different platforms. This software reuse holds the potential to revolutionize radio procurement economics by significantly increasing competition among platform vendors, leading to reduced per-unit costs.
Public safety agencies in the United States and other countries also struggle with interoperability problems when collaborating with other public safety agencies.
In major emergency situations, from floods to plane crashes, a large number of local, state and federal agencies respond to the scene each having a radio that may not be compatible with the radio used by another responding agency. The incompatible radios, ranging from legacy analog FM systems, to digital trunked radios and even commercial cell phones, leave the agencies unable to efficiently communicate with each other. Decentralized purchasing decisions typically lead to the situation where different agencies within different municipalities acquire the radio systems that best meet that particular agency's needs without the though of interoperability problems with other agencies with whom interaction is foreseeable. As a result of this acquisition process, the voice and data communications systems of different agencies cannot interoperate and their databases cannot share information.
In a mutual aid scenario, multiple agencies must work together and communicate with little opportunity for prior planning, frequently outside the range of fixed communications infrastructure and in difficult terrain. It is unknown when and where the response will be necessary, and who will be involved. Ensuring interoperability in this context requires an extremely flexible and rapidly deployable solution.
SDRs provide software control for a variety of modulation techniques, wide-band or narrow-band operation, communications security functions, and waveform requirements of current and evolving standards over a broad frequency range. SDR software modules may operate on a generic hardware platform consisting of digital signal processing and general purpose microprocessors used to implement radio functions such as generation of a transmitted signal at the transmitter and tuning/detection of a received radio signal at the receiver.
SDR can be used to implement military, commercial and civilian radio applications as described above. A wide range of radio applications including, but not limited to, AM, AMSSB, FM, PSK, QPSK, FSK, AMPS, GSM, Bluetooth, WLAN, GPS, Radar, WCDMA, GPRS, TDMA, QAM, FDMA, TDD, CDMA, etc. can be implemented using SDR technology.
The radio functions of SDR may be implemented as software modules. Multiple software modules that implement different standards can co-exist in the radio equipment and radios. An appropriate software module can be chosen to operate depending on, for example, network requirements. This enables in establishing multi-mode radios and equipment resulting in ubiquitous connectivity irrespective of the underlying network technology used.
SDR technology supports over the air upload of software modules to subscriber radios. This enables network operators as well as radio manufacturers to perform mass customization of radios by uploading appropriate software modules thereby resulting in faster deployment of new services and/or features.
One of the key features of SDR is its reconfigurability. SDR allows for the co-existence of multiple software modules implementing different standards on the same system allowing dynamic configuration of the system by selecting the appropriate software module to be run. This dynamic configuration is possible both in radios as well as infrastructure equipment. This ability to reconfigure facilitates implementation of future proof, multi-service, multi-mode, multi-band, multi-standard terminals and infrastructure equipment.
SDR enables implementation of air interface standards as software modules and multiple instances of such modules that implement different standards can co-exist in infrastructure equipment and radios. This capability is key in realizing global roaming facility.
The potential benefits of SDR are manifold. Up to now, the configuration and reconfiguration required to achieve these benefits of the SDR have involved time intensive effort. Trained personnel have been required to manually configure or select the software modules to enable operation of the SDR.
Currently, military communications systems require significant operator intervention during the setup and configuration prior to and during operations. This encumbers the dynamic reconfiguration potential of SDRs. An object of the present disclosure is the use of a smart card system to access layered information already programmed into the system. Another object is to significantly decrease the amount of time and personnel training required for establishing communications, thus enabling SDRs to better realize their full potential utility.
These and many other objects and advantages of the disclosed subject matter will be readily apparent to one skilled in the art to which the disclosure pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments.